First question: What is an athame
"traditionally" speaking, it's a ritual dagger with a double-edged blade, with a black handle that use to store and direct energy, draw a circle, cut an opening when leaving the circle. Athame shouldnt be use to actually cut something, with one exception of cutting handfasting cake
Second question: how is it made?
It can be made from various metal such as stainless steel or copper, some can be made out of carved stone or even wood.